ESP32 - Timestamps

[Florent]

Hi,

i'm using an ESP32 and a MPU9250 Sensor. I send the gyro values to a Java Server but the values have to get timestamped as soon as they arrive to the ESP32. Now the simple way would be to get the time via NTP-Client but there is a delay until the time arrives through the internet on my ESP32. I need to get precise timestamps and I can't allow delays happening when getting the current time. My question is how could I manage to get accurate timestamps without relying on the internet?

Thanks.

[lbernstone]

You can use a real time clock run off a battery.
https://www.aliexpress.com/item/32798201168.html